UCP1 and Mitochondrial myopathy: Mouse models, where an induction of both FGF21 and GDF15 was demonstrated include the Deletor mouse, a model for progressive mitochondrial myopathy [15], mCrif1 (CR6-interacting factor 1)-Ko mice with skeletal muscle specific disruption of oxidative phosphorylation [110], Aifm1 (apoptosis-inducing factor mitochondrion-associated 1)-knock-in mice, a model of severe myopathy [111], and, as the best studied muscle mitohormesis model, UCP1-tg mice [112, 113].